This application claims the benefit of Japanese Patent applications No. 2001-080875 and No. 2001-240946 which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a oneway clutch device for use in an automatic transmission, or the like, of an automobile, and more specifically, to a technology for facilitating a conveyance of clutch device subassemblies.
2. Related Background Art
Generally, an automatic transmission of an automobile is provided with, in addition to a torque converter which serves as a fluid coupling, a planetary geared transmission with three to five speed levels which carries out gear transmission by properly fixing or releasing the constituent elements (including a sun gear, or a planetary gear) of the planetary geared transmission by the use of frictional engagement means such as a clutch or a brake. As the frictional engagement means to be incorporated in the automatic transmission, a wet type multiple disc type device in which frictional plates and separator plates are alternately arranged is employed, except in band brakes of a certain type. A pressure oil from a transmission control oil hydraulic circuit is employed in the pressure contact (frictional engagement) between the both plates. Also as these frictional engagement means, there is partially employed a member having a oneway clutch device arranged therein for realizing easy control on the transmission by freely rotating a gear shaft in one direction of rotation.
FIG. 20 is a view for showing a longitudinal cross section of the essential portion of a oneway clutch device of a sprag type which is to be incorporated in the frictional engagement means. Referring to FIG. 20, the oneway clutch device 121 is composed of an inner race 5 which has an oil path 123 formed to open on the outer peripheral surface thereof, an outer race 9 which is rotatably supported coaxially and relatively with respect to this inner race 5, and a oneway clutch mechanism 125 interposed between the inner race 5 and the outer race 9. The oneway clutch mechanism 125 comprises a large number of sprags 127 serving as torque transmitting members, a ribbon spring 129 for holding the sprags 127 and, at the same time, for biasing the same in a direction of engagement, an outer retainer 131 for annularly retaining the ribbon spring 129, an inner retainer 133 for suppressing an excessive inclination of the sprags 127 together with the outer retainer 131, a pair of end bearings 135, 135 for holding the both retainers 131 and 133 with a predetermined distance therebetween so as to secure an operation of the sprags 127, and side plates 137 and 139 for restricting the axial movement of each of these components.
Oneway clutch devices 121 of this type are usually used in a state in which the inner race 5 is rotated while the outer race 9 is fixed, but also often used in a state in which the inner race 5 is fixed and the outer race 9 is rotated. In the latter case, lubricating oil can hardly flow between the inner race 5 and the sprags 127 or the end bearings 135, so that there may occur friction or scorching on a sliding surface due to poor lubrication. In addition, the end bearings 135 require high precision, so that the processing cost thereof is high, which is a factor for increasing a unit price of the oneway clutch device 121. Accordingly, employment of a oneway clutch device of a roller type is discussed in which rollers are interposed between the inner race and the outer race and a cam surface is formed on the inner race side. A oneway clutch device of the roller type comprises as its constituent parts springs for biasing the rollers to a direction of engagement, block bearings for forming a predetermined gap between the inner race and the outer race, and a retainer fitted on the inner race for retaining the rollers, springs and the block bearings.
With this roller type oneway clutch device, the problems described above can be solved, and at the same time, dragging torque in idling operation can be reduced. However, this roller type oneway clutch device has another problem that some of the constituent parts easily fall off in conveyance. More specifically, in the roller type oneway clutch device, the outer race as its constituent part serves as the output shaft or the input shaft of the automatic transmission, or the like, so that the outer race does not exist in the matter of course as a subassembly prior to the assembly of the automatic transmission or the like. Accordingly, if any impact is applied when the subassembly is conveyed, any of the rollers, the springs or the block bearings assembled in the inner race or the retainer falls off comparatively easily. In this case, a product must be rejected and is required to be disposed, which results in a lower working efficiency.
The present invention is contrived taking the above circumstances into consideration and its object is to provide a oneway clutch device capable of securely retaining its constituent parts by the use of a retainer, thereby enhancing the working efficiency in assembly.
In order to achieve the above object, according to a first aspect of the invention, there is proposed a oneway clutch device which comprises a plurality of rollers interposed between an inner race and an outer race for carrying out torque transmission only at the time of relative rotation in one direction between the inner race and the outer race, springs for biasing these rollers in a direction of engagement, and a retainer having an annular portion to be fitted on the inner race for retaining the rollers and the springs, wherein said retainer is formed with a roller latching piece formed for holding the rollers biased by said springs, together with said inner race in a state that it is not assembled in said outer race.
According to the first aspect of the invention, even if any impact is applied in conveyance of a subassembly, the rollers which are held by and between the roller latching piece of the retainer and the inner race do not fall off easily.
According to a second aspect of the present invention, there is proposed a oneway clutch device which comprises a plurality of rollers interposed between an inner race and an outer race for carrying out torque transmission only at the time of relative rotation in one direction between the inner race and the outer race, springs for biasing these rollers in a direction of engagement, and a retainer having an annular portion to be fitted on the inner race for retaining the rollers and the springs, wherein said retainer is provided with spring latching means formed for latching said springs.
According to the second aspect of the invention, even if any impact is applied in conveyance of a subassembly or in driving, the spring which is latched by said spring latching means of the retainer does not fall off easily.
According to a third aspect of the present invention, there is proposed a oneway clutch device which comprises a plurality of rollers interposed between an inner race and an outer race for carrying out torque transmission only at the time of relative rotation in one direction between the inner race and the outer race, springs for biasing these rollers in a direction of engagement, a block bearing for forming a predetermined gap between the inner race and the outer race, and a retainer having an annular portion to be fitted on the inner race for retaining the rollers, the springs and the block bearing, wherein said retainer is formed with a block bearing pressing piece formed for holding the block bearing together with said inner race in a state that it is not assembled in said outer race.
According to the third aspect of the invention, even if any impact is applied in conveyance of a subassembly or in driving, the block bearing which is held by and between the block bearing pressing piece of the retainer and the inner race does not fall off easily.
In addition, according to the oneway clutch of the present invention, said retainer may be formed of synthetic resin.
According to this aspect, even if the retainer has a comparatively complicated configuration, the manufacturing thereof can be carried out easily by using a metallic mold and, at the same time, the weight thereof can be reduced.